Fig. 3.

TEM images of particles without surface modifications (3A) and with both nanomachine and polymer modifications (3B). No major morphology or structural difference is observed after the surface modifications were applied. 3C shows the release profiles of the LPEI samples. Particles were kept in a neutral solution before acidification. No cargo leakage was observed under neutral pH and a large amount of cargo was released upon pH change in LPEI-1 and LPEI-3. The release amount is the weight percentage of the released cargos over the nanoparticles.